It is time for the human race to wake up to any leader who lets power get into their heads.

Sometimes it is not a leader but a very different Agency. A Hydra slithering out from the Company and the Usual Suspects. It continues regardless of "the leader" though sometimes it may appoint or allow a compromised leader to "lead" as a mouthpiece. Sometimes they really don't like the leader which the Democratic process elects. Then you get assassinations and very bad hot potatoes tossed into the fray. Sometimes the Dogs of War are paid for by the Agency and thrown into the ring in countries or states which need to be brought under Agency control. The mouthpieces of the Agency are then rolled out. False Flags and weird spin are the order of the day.
For an introduction on how this system operates I can thotoughly recommend L Fletcher Prouty who was in there. "Anatomy of An Assassination" is a very good place to start.